1. Field of the Invention
The invention relates to an apparatus for installing a new roof over an existing roof wherein the slope of the new roof can be independent of the slope of the existing roof. More particularly, the invention relates to a subframing support assembly for a new standing seam roof wherein the components are all standardized, pre-sized, and interchangeable in various combinations. Thus the builder can achieve the desired slope requirement for any roofing project without the need for field cutting any components.
2. Description of the Prior Art
One established method of erecting a new roof over an existing roof is to construct a support structure for the new roof on the existing roof. The lower part of the support structure is then attached to the existing roof structure. Next, the new roof structure is secured to the upper part of the support structure. The new roof structure generally consists of a number of roof panel members joined to each other and attached to underlying structural members commonly called "purlins." The purlins are what connects the new roof to the support structure.
Numerous types of new roof structures have heretofore been employed for buildings in efforts to provide a water tight roof assembly, while at the same time enabling the roof assembly to expand and contract as changes in temperature are encountered. Typical of such roof assemblies which have met with considerable success in recent years is the standing seam roof assembly. The panel members of a standing seam roof assembly are joined to each other along adjacent sides such that the sides are lapped together to form the standing seams. The panel members of the standing seam roof are then secured to structural members commonly referred to as "purlins". The interconnection of the panel members of the standing seam roof allow the roof structure to expand and contract as a function of the coefficient of expansion of the materials of which the roof panels are made and the temperature cycles to which the roof panels are exposed.
Standing seam roof assemblies are finding ever increasing usage in the "built-up" roof replacement segment of the roofing industry. Generally, a built-up roof is formed of a plurality of sections which are interconnected and overcoated with asphaltic composition to provide a water-tight seal. While such roof assemblies have generally served well, problems have nevertheless been encountered as a built-up roof ages, or when the building settles, or when the construction errors result in water standing in pockets on the roof assembly. This standing water can also result in deterioration of the roof causing leaks and the like to occur.
A need has long been recognized for a means for replacing such a built-up roof as well as other conventional roofs which does not require substantial modification of the pre-existing roof structure and which is economical in both fabrication and on-site construction. Further, it is highly desirable that the new roof assembly be capable of providing a new roof surface independent of the variations in the surface of the pre-existing roof assembly. Some past repair methods, especially those capable of altering the slope of the new roof to improve drainage characteristics, can require substantial destruction of the pre-existing roof and extensive custom construction. This can result in exposing the building and its contents to damage by the elements during the re-roofing process and can also be time consuming and expensive.
Some contemporary ways of providing a new roof on top of an existing roof are disclosed in U.S. Pat. Nos. 4,520,610 and 5,303,528, to Simpson, et. al. In each patent Simpson discloses a standing seam roof assembly and support apparatus for attaching a new roof on an existing roof which permits the slope of the new roof to be independent of the existing roof. In the '610 patent Simpson discloses using a series of adjustable truss members attached between the new roof and the existing roof. The height of the truss is adjustable so that the slope of the new roof can be set to the desired pitch by making the truss at the peak of the new roof a greater height than the truss at the lowest point of the new roof. Since the truss is adjustable, a series of identical trusses can be used with no field cutting of components required. The '528 patent additionally discloses a truss, or "elongated spanning member" supported by a series of independently vertically adjustable stanchions. The stanchions consist of interfitting longitudinally adjustable channel members which are lockable at variable heights. Thus, a series of spanning members supported by rows of vertically adjustable stanchions support the new roof on the existing roof at variable heights which can define the pitch of the new roof. Bearing plates are also disclosed between the stanchions and the existing roof. Also disclosed is that vertically adjustable members which have a lower member attachable to the existing roof and an upper member attachable to the new roof and including a web means which is pivotally connected to the upper or lower end so that it is also angularly adjustable with respect to the new roof. The upper member is attachable to a purlin clip for attaching the stanchion to a purlin which connects to the new roof. Additionally, the '528 patent discloses a Z-shaped roof support member consisting of two L-shaped member attached back to back in a Z-shape. Slots are provided in each so that the height may be adjusted vertically.
Another similar type of subframing assembly employs numerous rows of roof support members consisting of a base which attaches to the existing roof, a column member connected to the base, and a clip member affixed to the top of the column which attaches to a purlin for connection to the new roof. The column member and the base can be provided with a series of vertically spaced pre-drilled holes so that the height of the column can be adjusted to some extent by telescoping the end of the column in the base. The pre-drilled columns can be cut in various lengths to provide an initial overall height in addition to the vertical adjustment.
However, such field adjustable roof support assemblies can call for a multitude of system variations to accommodate particular job-to-job requirements. Some custom fabrication of the adjustable assembly for particular jobs can also be required prior to beginning construction. In addition, custom fabricated purlin clips for a particular pitch roof can be required.
Therefore, there is a need for a new roof subframing support assembly which is adaptable to virtually any retrofit roof application without the need for variations in the assembly system or custom fabrication or field cutting of any components. Moreover the new subframing support assembly should eliminate the need for custom fabricating the purlin clips for different pitch requirements.